In addition to what has already been said, you need to consider the orbital velocity of the planets, as it is different for each one, depending on their distance from the Sun, which exerts gravitational force on them. This results in the planets having to move faster to maintain the orbit. Because of this, we have for example Mercury with an average speed of 29.8 mi/s and Pluto with 2.95 mi/s.
For this reason Mercury will never be more than about 28 degrees away from the Sun, just as Venus will never be more than about 47 degrees away. This implies that very often Mercury and Venus will be in the same or adjacent house to the Sun.
So it would be extremely rare for a person to be born with each planet located on different astrological houses (even if we had 12 planets), because of their orbital velocity.